Wikipedia has some info about that.

An important event for the spread of the raccoon in Europe was the release of two pairs of raccoons on April 12, 1934 at Lake Edersee in Hesse. Four raccoons were released into the wild by forester Wilhelm Sittich Freiherr von Berlepsch at the request of the owner, poultry farmer Rolf Haag. The idea was that the released animals should enrich the local fauna and save the fur industry expensive imports.